The Sigma 100-400mm F5-6.3 DG OS HSM Contemporary is a 'compact' super-telephoto lens for full-frame Canon, Nikon and Sigma mounts. It has four special-low-dispersion elements, optical image stabilization, and an ultrasonic (HSM) focus motor. The lens has a push/pull zoom mechanism, a minimum shooting distance of 1.6m and a magnification of 0.26x. It is weather-sealed and uses 67mm – quite small for a lens with this focal range.